JP4977926B2

JP4977926B2 - Lead acid battery

Info

Publication number: JP4977926B2
Application number: JP2000031412A
Authority: JP
Inventors: 靖之吉原; 亜矢子平尾; 宣行高見; 一宏杉江
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2000-02-09
Filing date: 2000-02-09
Publication date: 2012-07-18
Anticipated expiration: 2020-02-09
Also published as: JP2001223013A

Description

【０００１】
【発明の属する技術分野】
本発明は、鉛蓄電池、特に環境温度に関係なく安定した電池寿命を要求される鉛蓄電池に関するものである。
【０００２】
【従来の技術】
鉛蓄電池は充放電を繰り返すサイクル用途、および過充電が主であるトリクル用途や自動車用途などに用いられているが、そのいずれの用途においても正極格子体の腐食が劣化主要因の一つとしてあげられる。
【０００３】
格子体は集電耳部と比較的太い肩骨、ならびに大部分を占めるマス目部から成り立っており、前記マス目部は格子骨と交点部によって形成されている。腐食が進行すると鉛合金が導電性の低い酸化鉛に変化するために格子体の導電性は低下し、また、各部分で伸びが発生するため、格子体−活物質間結合力の低下、活物質保持機能の低下を引き起こし、電池性能を低下させるという問題があった。
【０００４】
これを防ぐために格子体合金組成の改善により耐食性の向上を図るとともに、腐食をしても伸びを抑制するような格子体形状や、電流密度が大きく腐食しやすいと考えられる集電耳部付近の格子骨を他の部分の格子骨より太くして、効率放電時の電圧特性の低下を改善するとともに腐食が進行した場合でも格子骨断面積を確保するなどの格子体形状の改善によって電池性能の低下を抑制することが提案されてきた。
【０００５】
【発明が解決しようとする課題】
しかしながら、従来の構成では極板に温度分布が発生し、局部的な腐食が発生していた。この局部的な腐食は、環境温度が高い場合に顕著であり、従来、電流密度が大きく腐食が大きいと考えられていた極板上部よりも、放熱されにくく温度が上昇しやすい極板中央部での腐食が大きくなっていた。そのため、極板中央部で電流経路が切断され、他部の劣化が小さいにもかかわらず、電池特性の早期低下が起こり、それが電池の使用寿命になっていた。
【０００６】
また、使用機器の高性能化にともない電池へはコンパクト化と負荷の増大が要求されており、特に近年開発の進められている電気自動車用途では限られた空間内に電池が数多く設置され、これに加えて高率の放電や充電が行われるので高温になりやすく、電池の冷却方法とともに電池の高温耐久性の向上が重要な課題である。
【０００７】
本発明はこのような従来の課題を解決するものであり、環境温度にかかわらず寿命特性に優れる鉛蓄電池を提供することを目的とするものである。
【０００８】
【課題を解決するための手段】
上記目的を達成するために本発明は、鉛蓄電池用格子体において、集電耳部付近にある上部マス目の単位面積当たりの質量に比較して、前記上部マス目に続く中央部マス目の単位面積当たりの質量を同じ重さにし、かつ、前記中央部マス目の単位面積当たりの質量に比べて、下部マス目の単位面積当たりの質量を軽くして構成した格子体を備える鉛蓄電池としたものである。
【０００９】
【発明の実施の形態】
以下、本発明の実施の形態について、図１を参照しながら説明する。
【００１０】
極板の製作には鉛合金を圧延した帯状シート材料に切り目を入れ、展開して、マス目を形成するエキスパンド格子体１に連続的にペースト状活物質を塗着する方法を用いた。エキスパンド方式には金型カッターが上下して帯状シートに切り目を入れると同時に展開するレシプロ方式を用いた。このとき正極格子体については全体質量を同じとし、図１に示すように格子体を集電耳部２に近い上部から下部に向けてＡ，Ｂ，Ｃ各部の３部分に分割し、格子骨太さを変えることで各部分の質量を変化させた格子体を数種類作製した。ここで、従来例として各部質量が均一である電池をＮｏ．１、集電機能の向上を図るために格子上部であるＡ部の質量を他の部分であるＢ部とＣ部に比べて重くした電池をＮｏ．２、本発明の実施例として、格子体上部のＡ部から中央部のＢ部にかけて均一質量とし、下部であるＣ部の質量を小さくしＡ部からＢ部の質量増加を図った電池をＮｏ．３、格子体中央部であるＢ部をＡ部ならびにＣ部と比較して重くした電池をＮｏ．４とした。これらの格子体の各部分の質量比を表１に示す。
【００１１】
【表１】

【００１２】
ペースト状活物質は鉛酸化物を主成分とする粉体に水と硫酸を加え練合して作製し、これを前記格子体に同質量の活物質を塗着、熟成乾燥して極板を作製した。これら極板を正極６枚、負極７枚用いて群を構成した後、６セルを直列接続した定格１２Ｖ３０Ａｈの電池を作製した。なお、格子骨の太さをＡ，Ｂ，Ｃの各部で変化させるのはＡ，Ｂ，Ｃ部それぞれを段階的に変化させてもよいし、また段階的変化でなく順次変化させる形態とすることも本発明の実施の形態に含まれるものである。
【００１３】
【実施例】
以上のように構成された本発明の鉛蓄電池（Ｎｏ．３，Ｎｏ．４）と従来例の鉛蓄電池（Ｎｏ．１，Ｎｏ．２）について６０℃環境温度下で３ＣＡ放電サイクル寿命試験により評価を行った。なお、従来例の鉛蓄電池でこの評価を行うと正極の格子体の腐食によって寿命になることが判っている。このサイクル寿命試験では３ＣＡの定電流で８．４Ｖまで放電した後、２段定電流充電で充電をする過程を１サイクルとした。ここでいう２段定電流充電は１段目電流（０．２ＣＡ）で１４．４Ｖまで充電し、その後、２段目充電電流（０．０５ＣＡ）で４時間充電する方法である。
【００１４】
図２に５０℃、３ＣＡ放電サイクル寿命特性と電池種類の関係を示す。図２より、集電耳部付近にある上部格子骨の太さに比較して、順次これに続く格子骨の太さが格子体中央でも同じ太さにするか、もしくは格子体中央に行くに従いさらに太くし、かつ、格子体中央部の格子骨の太さに比べて下部格子骨の太さが順次細くなっている本発明の実施例の電池Ｎｏ．３，Ｎｏ．４の方が従来例の電池Ｎｏ．１やＮｏ．２よりも放電容量が大きく寿命特性に優れていることが判る。
【００１５】
また、電池Ｎｏ．１については分解し、極板から活物質と腐食層を取り除き重量を量ることでマス目部Ａ，Ｂ，Ｃの腐食量を調べた。このとき腐食量は以下の式に従って求めた。
【００１６】
（腐食量）＝（（初期重量）−（分解後重量））／（初期重量）×１００
その結果、Ｂ（５２％腐食）＞Ａ（４５％腐食）＞Ｃ（４２％腐食）の順序で腐食が進んでおり、図３に示すように極板中央部ほど腐食が進んでいることが確認できた。
【００１７】
以上の結果から、鉛蓄電池において、正極格子体の格子骨の太さを集電耳部付近にある上部格子骨の太さＴに比較して、順次これに続く格子骨の太さが格子体中央に行くに従い、同じ太さにするか、もしくはさらに太くすることにより高温使用時に顕著である正極格子体腐食が原因となる電池性能の低下を抑制し、寿命特性を向上させることができることが理解できる。
【００１８】
なお、上記実施例においては請求項２記載に係る発明に示すように格子体の単位面積当たりの質量を変化させる手段として格子骨の太さを変化させたが、請求項３記載に係る発明に示すように格子骨によるマス目面積を変化させることで単位面積当たりの質量を変化させる手段でも同様の実施効果が得られる。
【００１９】
さらに、本実施例においては格子体をレシプロエキスパンド方式によるものとしたが、幾重にも重なった円板状カッターで形成される型で帯状シートに切り込みを入れ、別工程で所定の幅寸法まで展開するロータリエキスパンド方式を用いた格子体についても同様の効果を得ることができる。加えて、鋳造格子を用いた場合も効果は同様に得られ、本発明は格子体製造工法を限定するものではない。
【００２０】
さらに、本発明はベント式鉛蓄電池において効果的であるが、充電時の酸素吸収サイクルなどの発熱反応があったり、電解液が少なく小熱容量のために温度上昇しやすい密閉式鉛蓄電池では、より効果が顕著である。
【００２１】
【発明の効果】
以上の説明で明らかなように本発明によれば、鉛蓄電池用格子体において、集電耳部付近にある上部格子骨の太さに比較して、これに続く格子骨の太さが中央部も同じにし、かつ、格子体中央部の格子骨の太さに比べて下部格子骨の太さを細くにすることにより高温使用時に顕著である正極格子体腐食が原因となる電池性能の低下を抑制し、寿命特性を向上させることができ、優れた鉛蓄電池を実現できるものである。
【図面の簡単な説明】
【図１】本発明の実施例並びに従来例を説明する格子体の側面図
【図２】本発明の実施例の電池と従来例の電池の放電容量とサイクル数を示した寿命特性比較図
【図３】従来例電池における寿命試験後の格子体各部の腐食量を示す図
【符号の説明】
１エキスパンド格子体
２集電耳部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lead-acid battery, particularly a lead-acid battery that requires a stable battery life regardless of the environmental temperature.
[0002]
[Prior art]
Lead-acid batteries are used for cycle applications that repeatedly charge and discharge, and trickle and automobile applications where overcharging is the main. Corrosion of the positive grid is one of the main causes of deterioration in any of these applications. It is done.
[0003]
The lattice body includes a current collecting ear portion, a relatively thick shoulder bone, and a grid portion that occupies most of the grid body, and the grid portion is formed by the grid bone and the intersection portion. As corrosion progresses, the lead alloy changes to lead oxide with low conductivity, and the conductivity of the lattice decreases. In addition, elongation occurs in each part. There was a problem that the battery holding performance was lowered due to a decrease in the substance holding function.
[0004]
In order to prevent this, the corrosion resistance is improved by improving the lattice alloy composition, and the shape of the lattice body that suppresses elongation even when corroded, and the vicinity of the current collecting ear that is considered to be easily corroded with a large current density By making the grid bone thicker than other grid bones, the degradation of the voltage characteristics during efficient discharge is improved, and even when corrosion progresses, the grid shape is improved, such as securing the grid bone cross-sectional area. It has been proposed to suppress the decline.
[0005]
[Problems to be solved by the invention]
However, in the conventional configuration, temperature distribution occurs in the electrode plate, and local corrosion occurs. This local corrosion is prominent when the environmental temperature is high, and it is more difficult to dissipate heat than the upper part of the electrode plate, which has been thought to have high current density and high corrosion. The corrosion of the was large. For this reason, the current path is cut at the center part of the electrode plate, and the deterioration of the other parts is small, but the battery characteristics are prematurely lowered, which is the service life of the battery.
[0006]
In addition, as the performance of the equipment used increases, the batteries are required to be more compact and the load to be increased. Especially in the electric vehicle applications that are being developed in recent years, many batteries are installed in a limited space. In addition, since high rate discharge and charging are performed, the temperature is likely to become high, and improvement of the high temperature durability of the battery is an important issue together with the cooling method of the battery.
[0007]
The present invention solves such conventional problems, and an object of the present invention is to provide a lead-acid battery having excellent life characteristics regardless of the environmental temperature.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in the lead-acid battery grid, compared to the mass per unit area of the upper cell in the vicinity of the current collecting ear, the central cell following the upper cell is provided. a weight per unit area at the same weight, and, in comparison with the mass per unit area of the central portion grids, a lead-acid battery comprising a grid constituted by lightly mass per unit area of the lower grid It is a thing.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIG.
[0010]
For production of the electrode plate, a method was used in which a strip-shaped sheet material obtained by rolling a lead alloy was cut and expanded, and a paste-like active material was continuously applied to the expanded lattice body 1 forming a grid. For the expanding method, a reciprocating method was used in which a mold cutter moves up and down and cuts into a belt-like sheet and develops at the same time. At this time, the positive electrode lattice body has the same overall mass, and as shown in FIG. 1, the lattice body is divided into three parts A, B and C from the upper part close to the current collecting ear part 2 to the lower part. Several types of lattices were produced by changing the mass and changing the mass of each part. Here, as a conventional example, a battery in which the mass of each part is uniform is No. 1. In order to improve the current collecting function, a battery in which the mass of the A part, which is the upper part of the lattice, is heavier than that of the other parts B and C is No. 2. As an example of the present invention, a battery having a uniform mass from the A part at the upper part of the lattice body to the B part at the central part, the mass of the lower part C being reduced, and the mass increasing from the A part to the B part being No. . 3. A battery in which the B part, which is the central part of the lattice body, is heavier than the A part and the C part. It was set to 4. Table 1 shows the mass ratio of each part of these lattice bodies.
[0011]
[Table 1]

[0012]
The paste-like active material is prepared by adding water and sulfuric acid to a powder containing lead oxide as a main component, kneading, and applying the same mass of active material to the lattice, aging and drying to form an electrode plate. Produced. After forming a group using these electrode plates with 6 positive electrodes and 7 negative electrodes, a battery having a rating of 12V30Ah in which 6 cells were connected in series was produced. It should be noted that the thickness of the lattice bone is changed at each of the A, B, and C portions, each of the A, B, and C portions may be changed stepwise, or may be changed sequentially instead of stepwise. This is also included in the embodiment of the present invention.
[0013]
【Example】
The lead storage battery (No. 3, No. 4) of the present invention configured as described above and the conventional lead storage battery (No. 1, No. 2) were evaluated by a 3CA discharge cycle life test at an ambient temperature of 60 ° C. Went. In addition, when this evaluation is performed with the lead-acid battery of the conventional example, it is known that the lifetime is increased due to corrosion of the positive electrode lattice. In this cycle life test, the process of charging with two-stage constant current charging after discharging to 8.4 V with a constant current of 3 CA was defined as one cycle. Here, the two-stage constant current charging is a method of charging to 14.4 V with the first stage current (0.2 CA) and then charging with the second stage charging current (0.05 CA) for 4 hours.
[0014]
FIG. 2 shows the relationship between the 50 ° C., 3CA discharge cycle life characteristics and the battery type. From FIG. 2, compared to the thickness of the upper lattice bone near the current collecting ear, the thickness of the subsequent lattice bone is made the same thickness at the center of the lattice body, or as it goes to the center of the lattice body The battery No. 1 of the embodiment of the present invention is further thickened and the thickness of the lower lattice bone is successively thinner than the thickness of the lattice bone at the center of the lattice body. 3, No. No. 4 is the battery No. of the conventional example. 1 or No. It can be seen that the discharge capacity is larger than 2, and the life characteristics are excellent.
[0015]
Battery No. 1 was disassembled, the active material and the corrosive layer were removed from the electrode plate, and the weight of the grids A, B, and C was examined by weighing. At this time, the amount of corrosion was determined according to the following equation.
[0016]
(Corrosion amount) = ((initial weight) − (weight after decomposition)) / (initial weight) × 100
As a result, the corrosion progresses in the order of B (52% corrosion)> A (45% corrosion)> C (42% corrosion), and as shown in FIG. It could be confirmed.
[0017]
From the above results, in the lead storage battery, the thickness of the grid bone of the positive grid is compared with the thickness T of the upper grid bone in the vicinity of the current collector ear, As you go to the center, it is understood that by making the same thickness or even thicker, it can suppress the deterioration of battery performance caused by positive grid corrosion, which is remarkable at high temperature use, and can improve the life characteristics it can.
[0018]
In the above embodiment, the thickness of the lattice bone is changed as means for changing the mass per unit area of the lattice body as shown in the invention according to claim 2, but the invention according to claim 3 As shown, the same effect can be obtained by means of changing the mass per unit area by changing the grid area of the lattice bone.
[0019]
Furthermore, in this example, the lattice body is based on the reciprocating expand method, but the band-shaped sheet is cut with a mold formed by overlapping disk-shaped cutters, and developed to a predetermined width dimension in a separate process. The same effect can be obtained for the lattice body using the rotary expanding system. In addition, the same effect can be obtained when a cast lattice is used, and the present invention does not limit the method of manufacturing the lattice body.
[0020]
Furthermore, the present invention is effective in a bent type lead storage battery. However, in a sealed lead storage battery that has an exothermic reaction such as an oxygen absorption cycle at the time of charging, or has a low electrolyte and easily rises in temperature due to a small heat capacity, The effect is remarkable.
[0021]
【Effect of the invention】
As is clear from the above description, according to the present invention, in the lead-acid battery lattice, the thickness of the lattice bone following this is compared with the thickness of the upper lattice bone near the current collecting ear portion. also the same, and a reduction positive electrode grid corrosion cell performance that causes a noticeable at high temperatures used by the thinner the thickness of the lower lattice bone as compared to the thickness of the grating bone grid central portion It can suppress, can improve a life characteristic, and can implement | achieve the outstanding lead acid battery.
[Brief description of the drawings]
FIG. 1 is a side view of a lattice for explaining an embodiment of the present invention and a conventional example. FIG. 2 is a life characteristic comparison diagram showing discharge capacity and cycle number of the battery of the embodiment of the present invention and the battery of the conventional example. FIG. 3 is a diagram showing the amount of corrosion of each part of a grid after a life test in a conventional battery.
1 Expanded grid 2 Current collecting ear

Claims

In grid for a lead-acid battery, as compared to the mass per unit area of the upper squares in the vicinity of the current collector lug part, the mass per unit area of the central portion squares following the upper grid, the same weight And the lead storage battery characterized by including the grid | lattice body comprised by making the mass per unit area of the lower cell lighter compared with the mass per unit area of the said center part cell.

In grid for a lead-acid battery, as compared to the thickness of the upper grid bone in vicinity of the current collector lug part, the thickness of the central portion grating bone following the upper lattice bone, the same thickness, and said central portion The lead-acid battery according to claim 1, further comprising a lattice body configured by making the thickness of the lower lattice bone thinner than the thickness of the lattice bone.

In the lead-acid battery grid, the grid area by the central grid bone following the grid by the upper grid bone is compared to the grid area by the upper grid bone near the current collecting ear. the eye surface product, and, according to claim 1, characterized in that it comprises a grid configured with a larger grid area due lower lattice bone compared to square area by the central grid bone Lead acid battery.

The lead-acid battery according to claim 1, wherein an expanded lattice processed from a strip-shaped sheet material made of lead or a lead alloy is used as a lattice.

The lead acid battery according to claim 1, wherein the battery is a sealed battery.